1. Field of the Invention
The present invention relates to a solid-state image sensor and a camera.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2001-250931 discloses a solid-state image sensor having a focus detection function. In such a solid-state image sensor, a photodiode in each pixel for focus detection is divided into two photodiodes to form two images having a given parallax. By detecting the phase difference between these two images, the amount of defocus can be obtained.
The two divided photodiodes provided in each pixel to obtain a phase difference signal for focus detection are arranged close to each other. Charges generated by light incident on the vicinity of the boundary between the two photodiodes may be accumulated in both these photodiodes. A phenomenon in which charges generated by light incident on one photodiode are accumulated in the other photodiode can be understood as crosstalk, which may lower the accuracy and rate of phase-difference detection. On the other hand, when the distance between the two photodiodes is increased so as to reduce the crosstalk, the region for photoelectrically converting incident light widens, thus degrading the light detection sensitivity.